Batteries with high energy density and high discharge rate capabilities are desirable for certain applications. This is especially true when the batteries are used in devices where the batteries are difficult to replace and/or recharge, such as in an implantable medical device (IMD). An end-of-life (EOL) indicator for the battery may also be an important feature for this kind of application. A silver vanadium oxide (SVO) cathode material offers high discharge rate capability and a good EOL indicator because of its sloped discharge voltage curve. Sub-fluorinated carbon fluoride (CFx) offers higher energy density, but it has low discharge rate capability and no EOL indicator.
There have been some attempts to produce a CFx/SVO hybrid battery. For example, a three-layer sandwiched design has been proposed having two SVO outer layers and one CFx center layer with a current collector in-between each SVO/CFx interface. A drawback of this design is its low packing efficiency, as two layers of current collector are needed for each cathode plate. Another design includes a mixed chemistry cathode, where the CFx and SVO are physically blended together and treated as one material bonded to a current collector. This design suffers from a lower discharge rate capability compared to an SVO-only cathode material.